Hi Ash77,
I'm sorry to hear how things have taken a turn for the worse. People with BPD have extreme rejection sensitivity and an intense fear of abandonment, and this can trigger very defensive reactions. Those reactions often end up destroying the exact relationships they fear losing. These pervasive fears make it hard for them to form intimate bonds and trust, and this puts us in a tenuous situation because we end up feeling like we're shadowboxing with something we can't see.
The first thing to do is end the destructive dance -- as much as you can (and this is hard), don't engage the drama. That means choosing to not debate, justify, explain, or defend yourself. There are proven communication skills that can help, and setting boundaries and
creating a validating environment can all work together to make things less toxic.
You can't control how she thinks or what she does. You can control how you think and what you do -- part of being with someone who has BPD is accepting the realities of the disorder. She is hypersensitive to abandonment. That means even something as simple as going into another room, or looking at your phone when she's talking to you, can be a challenge for her. She's feeling intense emotions and has few skills to emotionally regulate herself. In those moments, you'll have to validate how she feels and if things escalate despite the validation, assert your boundaries.
It takes a lot of strength to not be emotionally injured in a BPD relationship. And as much as she may make it difficult for you to be this way, she also needs you to be strong and provide structure.